Marking compositions are well known in the art that are formulated from combinations of waxes, fatty acids, colorants, color extenders, and other additives. These marking compositions can be used to fabricate crayons, which can be used to draw, write, or color on porous and non-porous substrates. Crayons are most often used by children on various types of paper, such as notebook paper, art paper, and posterboard. Furthermore, crayons are available in a wide selection of colors, ranging from primary colors to fluorescent colors.
A variety of crayons and marking compositions have been disclosed in the patent literature. See, for example, U.S. Pat. Nos. 3,409,574, 3,933,708, 4,212,676, 4,990,013, and 5,383,954. Despite this availability, consumers desire crayons with improved properties to obtain better laydown and better drawing qualities as well as less flaking from completed drawings using the crayons.
Laydown is a measure of the smoothness qualities with which the writing composition transfers to the writing surface. Children prefer crayons having improved laydown since they can produce marks and crayon drawings while exerting minimal pressure on the crayon. Smooth and slick color laydown is especially important to children who are mentally or physically impaired. An added benefit which is especially desired by children is that a crayon having improved laydown characteristics yields marks having richer and more brilliant colors. While the crayons of U.S. Pat. No. 5,383,954 are excellent crayons, in use the crayons yield a considerable amount of flaking. Flaking, or loose particles of crayon material, can present a clean-up problem in the home when children use crayons which flake since the flakes can be ground into the working surface or, as is often the case, home carpeting.
Others have proposed that laydown of crayons may be improved by increasing the amounts of emollients, for example, oils such as castor oil, in the crayon formulation. Although this approach has had some success in improving laydown, the emollient adversely affects other desirable properties of the marking composition. For example, the strength of the writing instrument made from such compositions decreases resulting in manufacturing problems as well as problems in the use of these writing instruments. For example, writing instruments such as crayons formed from such compositions break or crumble rather easily, especially when used by children.
The use of greater amounts of emollients also adversely affects the tackiness of the writing instrument. For example, the writing instrument becomes excessively tacky to the touch, especially when held between the fingers during writing. This excessive tackiness creates an unpleasant feeling for the user. There may also be excessive transfer of some of the components of the writing composition, for example, the pigment, to the user's hands or clothes. The excessive transfer of materials, besides creating an unpleasant feeling to the user, can cause unnecessary stains to the hands and clothes as well as in areas such as carpets where children use the crayons.
One attempt to create a better children's crayon is found in U.S. Pat. No. 5,383,954 by the present inventor. The glitter crayon disclosed in the patent excels at trapping glitter on a page when a mark is made. The crayons made according to this patent exhibit significant levels of product laydown with accompanying high levels of flaking of excess crayon material.
Thus, there remains a need for a marking composition that has the desirable laydown characteristics. More particularly, there is a need for a marking composition that minimizes friction between the crayon and the substrate to allow for a smooth and slick laydown of color with minimal exertion of pressure by the user. There also remains a need for a marking composition with improved laydown properties that is not overly tacky to the touch and does not exhibit excessive flaking. There further remains a need for a marking composition having improved laydown properties which does not excessively transfer materials to the hands or clothes of the user. There further remains a need for a marking composition having improved laydown characteristics that has the desirable mechanical strength to withstand use by children.
These and other objects and advantages of the present invention, as well as additional inventive features, will become apparent from the description of the present invention provided herein.